John Houck has created this really interesting installation, here’s his description of the guts of the piece:

This installation contains 35 motors that are controlled individually with an arduino microcontroller. Processing is used to send commands, via serial communication, to the arduino. The sequencing of the motors changing speed was inspired by the movement of people through public spaces.

The project is called Volumes of Emptiness and although the website doesn’t actually say where it’s exhibiting, there are some great photos and videos of the work in action. Looks like a very interesting and lively installation. I’d love to see a more concise write up about the logistics of the project.